Able to reproduce the issue on Windows-7 using chrome latest Dev M54-54.0.2832.0. No issues observed on Windows-10. Will update the Linux and Mac behavior soon once the build is available.

Additional repro steps:
-------------------------
1. Play videos from Youtube.com
2. Click on YoutTube icon on the top to navigate to youtube home page
3. Now try clicking on any videos
4. Page goes unresponsive and kill the tab it crashes

Note: 
------
1. For consistent repros we need to click the different videos continuously. 
2. Issue is able to reproduce it on Windows-10 as well.
3. Marking it as RB-Dev for now, Please feel free to edit or remove if this is not the case.

Crash ID's:
---------------
9ee4532100000000 - Windows-7
8388d32100000000 - Windows-10 

Stack Trace:
-------------
Thread 0 MAGIC SIGNATURE THREAD
0x000007feca0ca53b	(chrome_child.dll -flattreetraversal.cpp:43 )	blink::canBeDistributedToInsertionPoint
0x000007feca0cab2d	(chrome_child.dll -flattreetraversal.cpp:169 )	blink::FlatTreeTraversal::traverseParent(blink::Node const &,blink::LayoutTreeBuilderTraversal::ParentDetails *)
0x000007feca0627e4	(chrome_child.dll -node.cpp:951 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0627fb	(chrome_child.dll -node.cpp:952 )	blink::Node::canStartSelection()
0x000007feca0e6e52	(chrome_child.dll -eventhandler.cpp:761 )	blink::EventHandler::selectAutoCursor(blink::HitTestResult const &,blink::Node *,blink::Cursor const &)
0x000007feca0e6a79	(chrome_child.dll -eventhandler.cpp:661 )	blink::EventHandler::selectCursor(blink::HitTestResult const &)
0x000007feca0e8360	(chrome_child.dll -eventhandler.cpp:1061 )	blink::EventHandler::handleMouseMoveOrLeaveEvent(blink::PlatformMouseEvent const &,blink::HitTestResult *,bool,bool)
0x000007feca0e7b4a	(chrome_child.dll -eventhandler.cpp:944 )	blink::EventHandler::handleMouseMoveEvent(blink::PlatformMouseEvent const &)
0x000007fecb4f1323	(chrome_child.dll -pagewidgetdelegate.cpp:206 )	blink::PageWidgetEventHandler::handleMouseMove(blink::LocalFrame &,blink::WebMouseEvent const &)
0x000007fecb4f1175	(chrome_child.dll -pagewidgetdelegate.cpp:137 )	blink::PageWidgetDelegate::handleInputEvent(blink::PageWidgetEventHandler &,blink::WebInputEvent const &,blink::LocalFrame *)
0x000007fecb4d3355	(chrome_child.dll -webviewimpl.cpp:2221 )	blink::WebViewImpl::handleInputEvent(blink::WebInputEvent const &)
0x000007fecb8c8946	(chrome_child.dll -render_widget_input_handler.cc:324 )	content::RenderWidgetInputHandler::HandleInputEvent(blink::WebInputEvent const &,ui::LatencyInfo const &,content::InputEventDispatchType)
0x000007fecb8359f1	(chrome_child.dll -render_widget.cc:675 )	content::RenderWidget::OnHandleInputEvent(blink::WebInputEvent const *,ui::LatencyInfo const &,content::InputEventDispatchType)
0x000007fecb8322b6	(chrome_child.dll -ipc_message_templates.h:121 )	IPC::MessageT<InputMsg_HandleInputEvent_Meta,std::tuple<blink::WebInputEvent const *,ui::LatencyInfo,content::InputEventDispatchType>,void>::Dispatch<content::RenderWidget,content::RenderWidget,void,void ( content::RenderWidget::*)(blink::WebInputEvent const *,ui::LatencyInfo const &,content::InputEventDispatchType)>(IPC::Message const *,content::RenderWidget *,content::RenderWidget *,void *,void ( content::RenderWidget::*)(blink::WebInputEvent const *,ui::LatencyInfo const &,content::InputEventDispatchType))
0x000007fecb836506	(chrome_child.dll -render_widget.cc:473 )	content::RenderWidget::OnMessageReceived(IPC::Message const &)
0x000007fecb808006	(chrome_child.dll -render_view_impl.cc:1379 )	content::RenderViewImpl::OnMessageReceived(IPC::Message const &)
0x000007fecbc93237	(chrome_child.dll -message_router.cc:52 )	IPC::MessageRouter::RouteMessage(IPC::Message const &)
0x000007fecb3bffeb	(chrome_child.dll -child_thread_impl.cc:773 )	content::ChildThreadImpl::OnMessageReceived(IPC::Message const &)
0x000007fecb1cfe23	(chrome_child.dll -bind_internal.h:303 )	base::internal::InvokeHelper<1,void>::MakeItSo<void ( media::DXVAVideoDecodeAccelerator::*const &)(media::VideoDecodeAccelerator::Config const &),base::WeakPtr<media::DXVAVideoDecodeAccelerator> const &,media::VideoDecodeAccelerator::Config const &>(void ( media::DXVAVideoDecodeAccelerator::*const &)(media::VideoDecodeAccelerator::Config const &),base::WeakPtr<media::DXVAVideoDecodeAccelerator> const &,media::VideoDecodeAccelerator::Config const &)
0x000007fecb8a4295	(chrome_child.dll -input_event_filter.cc:254 )	content::InputEventFilter::HandleEventOnMainThread(int,blink::WebInputEvent const *,ui::LatencyInfo const &,content::InputEventDispatchType)
0x000007fecb8f4048	(chrome_child.dll -main_thread_event_queue.cc:108 )	content::MainThreadEventQueue::PopEventOnMainThread()
0x000007fec9c32572	(chrome_child.dll -task_annotator.cc:54 )	base::debug::TaskAnnotator::RunTask(char const *,base::PendingTask const &)
0x000007fecb48835c	(chrome_child.dll -task_queue_manager.cc:315 )	blink::scheduler::TaskQueueManager::ProcessTaskFromWorkQueue(blink::scheduler::internal::WorkQueue *,blink::scheduler::internal::TaskQueueImpl::Task *)
0x000007fecb487944	(chrome_child.dll -task_queue_manager.cc:218 )	blink::scheduler::TaskQueueManager::DoWork(base::TimeTicks,bool)
0x000007fecb8f45ba	(chrome_child.dll -bind_internal.h:303 )	base::internal::InvokeHelper<1,void>::MakeItSo<void ( content::AudioRendererSinkCacheImpl::*const &)(media::AudioRendererSink const *,bool),base::WeakPtr<content::AudioRendererSinkCacheImpl> const &,media::AudioRendererSink const * const &,bool const &>(void ( content::AudioRendererSinkCacheImpl::*const &)(media::AudioRendererSink const *,bool),base::WeakPtr<content::AudioRendererSinkCacheImpl> const &,media::AudioRendererSink const * const &,bool const &)
0x000007fec9c32572	(chrome_child.dll -task_annotator.cc:54 )	base::debug::TaskAnnotator::RunTask(char const *,base::PendingTask const &)
0x000007fec9bcbfb7	(chrome_child.dll -message_loop.cc:488 )	base::MessageLoop::RunTask(base::PendingTask const &)
0x000007fec9bccea4	(chrome_child.dll -message_loop.cc:621 )	base::MessageLoop::DoWork()
0x000007fec9c34216	(chrome_child.dll -message_pump_default.cc:35 )	base::MessagePumpDefault::Run(base::MessagePump::Delegate *)
0x000007fec9c1e95c	(chrome_child.dll -run_loop.cc:35 )	base::RunLoop::Run()
0x000007fecb80cccb	(chrome_child.dll -renderer_main.cc:198 )	content::RendererMain(content::MainFunctionParams const &)
0x000007fecace3bfe	(chrome_child.dll -content_main_runner.cc:418 )	content::RunNamedProcessTypeMain(std::basic_string<char,std::char_traits<char>,std::allocator<char> > const &,content::MainFunctionParams const &,content::ContentMainDelegate *)
0x000007fecace3a3a	(chrome_child.dll -content_main_runner.cc:785 )	content::ContentMainRunnerImpl::Run()
0x000007fecace2e87	(chrome_child.dll -content_main.cc:20 )	content::ContentMain(content::ContentMainParams const &)
0x000007feca87eafd	(chrome_child.dll -chrome_main.cc:85 )	ChromeMain
0x000000013f2aa95d	(chrome.exe -main_dll_loader_win.cc:183 )	MainDllLoader::Launch(HINSTANCE__ *)
0x000000013f2a9ac3	(chrome.exe -chrome_exe_main_win.cc:250 )	wWinMain
0x000000013f494a4d	(chrome.exe -exe_common.inl:255 )	__scrt_common_main_seh
0x777d59bc	(kernel32.dll + 0x000159bc )	BaseThreadInitThunk
0x77a0a2e0	(ntdll.dll + 0x0002a2e0 )	RtlUserThreadStart


Bisect Information:
---------------------
Good build: 54.0.2831.0 
Bad Build : 54.0.2832.0 

Change Log URL: https://chromium.googlesource.com/chromium/src/+log/a2e00444025eca4d094285409c85b8fbbb8a26ac..bffc32eb63e5e211a1f2bd44cae8c91bc5ac2922

From the above change log suspecting below change

Review-Url: https://codereview.chromium.org/2021793002

yoichio@ - Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Thanks!

Issue is also seen on Linux OS

Deleted: Actual_Video.webm 1.5 MB

	Actual_Video.webm 1.5 MB View Download

Reproducible on the latest canary(54.0.2832.0) on Mac OS 10.11.5 as well.

There are 8 out of 11  different variant of magic signatures(same regression range and suspect) on the latest canary(54.0.2832.0- crash data of 2 hours) of Windows. No crash data for Mac canary(triggered 1 hour ago) is generated yet to update the behaviour.

Various Magic signatures:
==========================
1. [Renderer hang] blink::FlatTreeTraversal::traverseParent. Crash id: 8367372200000000
2. [Renderer hang] blink::FlatTreeTraversal::traverseParentOrHost. Crash id: f1d9d72200000000
3. [Renderer hang] blink::canBeDistributedToInsertionPoint. Crash id: 6ff5ab2100000000
4. [Renderer hang] blink::HTMLElement::draggable. Crash id: 11ced72200000000
5. [Renderer hang] blink::hasEditableLevel. Crash id: e87b372200000000
6. [Renderer hang] blink::Node::canStartSelection. Crash id: ced3fde900000000
7. [Renderer hang] blink::Node::isChildOfV0ShadowHost. Crash id: 12e4f32100000000
8. [Renderer hang] blink::AttributeCollectionGeneric<blink::AttributeArray const ,blink::AttributeArray const >::find. Crash id: 2a072b2100000000

yoichio@: Can we get an update on this as this is blocking today's Dev release. Cc'ing reviewers as well for more inputs.


Note: Canary was pushed late to the users due to Issue 638809. That's why there are very less crash data as of now. This would probably spike further with more crash data coming in. Requesting MTV team to follow up on this.

Restrict-View for Crash issue.

Short Link to the list of the magic signatures on Windows chrome canary: https://goto.google.com/mcgsz 

This or a similar issue causes renderer hangs on today's Mac canary (54.0.2832.0). Sampling of hung renderers shows they are spending 100% of their time in blink::Node::canStartSelection().

ajha@, I don't think this crash is sensitive, and many canary users will hit this bug today - can we open this bug back up so they can see it?

Sure  ellyjones@. Removing Restrict view per C#7.

I got [Renderer hang] blink::Node::isChildOfV0ShadowHost today on my main corp machine. crash/c5272f2200000000. Chrome 54.0.2832.0

In fact, Chrome 54.0.2832.0 canary (64-bit) seems totally unusable at the moment on Windows. Gmail tab hangs reliably every time I load it.

If https://codereview.chromium.org/2021793002 is the suspected CL it should be reverted.

I confirmed by looking at crashes that 08acdf950e1776571def8e6f16c288769e7e9e27 is definitely the culprit CL so I am reverting it now.

Thank you wfh@ for reverting the culprit CL.

Gmail tab hanging bug is being tracked in issue 638973

Issue 638973 has been merged into this issue.

it's all the same issue, and this will contain the revert, so duping everything to here.

Thanks! Removing from stability sheriff queue as this seems under control.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/29cd7243aa6537f9e1517568a299e8187bb3b230

commit 29cd7243aa6537f9e1517568a299e8187bb3b230
Author: wfh <wfh@chromium.org>
Date: Thu Aug 18 18:54:29 2016

Revert of [Editing][CSS] Drag from a -webkit-user-select:none element should not start selection (patchset #3 id:80001 of https://codereview.chromium.org/2021793002/ )

Reason for revert:
this is causing hangs on latest canary.  crbug.com/638868 

Original issue's description:
> [Editing][CSS] Drag from a -webkit-user-select:none element should not start selection
>
> This CL is updated of reverted one:
> https://codereview.chromium.org/2001993002
>
> This CL considers the reverted shadow boundary issue.
>
> BUG= 481985 
>
> Committed: https://crrev.com/08acdf950e1776571def8e6f16c288769e7e9e27
> Cr-Commit-Position: refs/heads/master@{#412457}

TBR=tkent@chromium.org,yosin@chromium.org,yoichio@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG= 481985 , 638868 

Review-Url: https://codereview.chromium.org/2256083003
Cr-Commit-Position: refs/heads/master@{#412903}

[modify] https://crrev.com/29cd7243aa6537f9e1517568a299e8187bb3b230/third_party/WebKit/LayoutTests/editing/selection/mouse/drag_user_select_none.html
[delete] https://crrev.com/196420669e24edf2ba2d8d2811e690232bcac9ad/third_party/WebKit/LayoutTests/editing/selection/mouse/select_user_select_in_shadow.html
[modify] https://crrev.com/29cd7243aa6537f9e1517568a299e8187bb3b230/third_party/WebKit/Source/core/dom/Node.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/930a07e51ed363faa31a9f54625c86da1ee171e5

commit 930a07e51ed363faa31a9f54625c86da1ee171e5
Author: Will Harris <wfh@chromium.org>
Date: Thu Aug 18 19:51:42 2016

Merge 2832: Revert of [Editing][CSS] Drag from a -webkit-user-select:none element should not start selection (patchset #3 id:80001 of https://codereview.chromium.org/2021793002/ )

Reason for revert:
this is causing hangs on latest canary.  crbug.com/638868 

Original issue's description:
> [Editing][CSS] Drag from a -webkit-user-select:none element should not start selection
>
> This CL is updated of reverted one:
> https://codereview.chromium.org/2001993002
>
> This CL considers the reverted shadow boundary issue.
>
> BUG= 481985 
>
> Committed: https://crrev.com/08acdf950e1776571def8e6f16c288769e7e9e27
> Cr-Commit-Position: refs/heads/master@{#412457}

TBR=tkent@chromium.org,yosin@chromium.org,yoichio@chromium.org
BUG= 481985 , 638868 

Review-Url: https://codereview.chromium.org/2256083003
Cr-Commit-Position: refs/heads/master@{#412903}
(cherry picked from commit 29cd7243aa6537f9e1517568a299e8187bb3b230)

Review URL: https://codereview.chromium.org/2257203003 .

Cr-Commit-Position: refs/branch-heads/2832@{#2}
Cr-Branched-From: 6c7eba987dc174e1522212efec1676619aa26a5a-refs/heads/master@{#412743}

[modify] https://crrev.com/930a07e51ed363faa31a9f54625c86da1ee171e5/third_party/WebKit/LayoutTests/editing/selection/mouse/drag_user_select_none.html
[delete] https://crrev.com/aa8710c62e2b42c85ffba2b45bc8d9e3ab899954/third_party/WebKit/LayoutTests/editing/selection/mouse/select_user_select_in_shadow.html
[modify] https://crrev.com/930a07e51ed363faa31a9f54625c86da1ee171e5/third_party/WebKit/Source/core/dom/Node.cpp

 Issue 639116  has been merged into this issue.

Let's please figure out how to write regression tests for this issue so it doesn't happen again. Thanks.

Users experienced this crash on the following builds:

Win Canary 54.0.2832.0 -  247.19 CPM, 805 reports, 672 clients (signature [Renderer hang] blink::FlatTreeTraversal::traverseParent)
Win Canary 54.0.2832.0 -  140.64 CPM, 458 reports, 413 clients (signature [Renderer hang] blink::canBeDistributedToInsertionPoint)

If this update was incorrect, please add "Fracas-Wrong" label to prevent future updates.

- Go/Fracas

Thanks all for fixing the issue.
We should have more D&D tests on shadow DOM trees.

Issue is not seen on latest  54.0.2832.2 Build.
Verified YouTube,Gmail,Crbug.com,Google search etc
Attaching Video for Reference

Deleted: VerifiedOn54.0.2832.2Build.ogv 7.5 MB

	VerifiedOn54.0.2832.2Build.ogv 7.5 MB View Download

Tested this issue on Windows-10 and Ubuntu 14.04 using chrome latest canary M54-54.0.2832.2 and observed no issues in playing videos.

Tested the same on Mac OS 10.11.6 using chrome latest canary and still the issue is observed on edition.cnn.com and foxnews.com, No issues seen on playing YouTube videos.

Steps to repro:
----------------
1. Navigate to Edition.cnn.com or Foxnews.com
2. Wait until the page loads completely
3. Click on any videos or links from the page
4. At first time no issues are seen in playing videos or opening links
5. Click on home page
6. Follow steps 2 & 3
7. Unable to navigate to any of the links

Bisect Information:
---------------------
Good build: 54.0.2831.0 
Bad Build : 54.0.2832.0 

Unable to provide the tool bisect CL due to continuous good builds, so providing manual CL from omahaproxy

Change Log URL: 
---------------
https://chromium.googlesource.com/chromium/src/+log/54.0.2831.0..54.0.2832.0?pretty=fuller&n=10000

Could anyone please check this issue, Attaching screen-cast for reference. Please let us know is this is the same bug or do we need to file a different one for this issue?

Thanks!

Deleted: 638868.mp4 2.7 MB

	638868.mp4 2.7 MB View Download

Tried Bisecting the issue with below steps:
Steps:
======
1) Open chrome and search "Olympics 2016"(or anything)
2) Able to click on the links of the page
3) Now scroll once down/up and try clicking the links
4) The links are not clickable even if the page is refreshed/reloaded.
Attached screen cast of the same for reference.

The issue is seen only on Mac and working fine on Win and Linux.

Bisect info:
=============
Good: 54.0.2830.0/54.0.2831.0
Bad : 54.0.2832.0

Change Log:
https://chromium.googlesource.com/chromium/src/+log/7f781f34f09fe2f3c5117f71de47e38d9bb59bad..806556451c84f03082ece3818862bbc22fd2727b

Possible suspect : https://codereview.chromium.org/2245393002
yosin@ : Could you please take a look into this if its the cause.

Deleted: 638868_Mac.mp4 3.9 MB

	638868_Mac.mp4 3.9 MB View Download

Filed a new  issue 639501  to track the Mac OSX bug in # 24. 

The bug shown in # 24 on Mac OSX is tracked in  issue 639046  [Fixed already]

yoichio/wfh@, can you please mark this bug as Fixed as the original issue reported in description is not seen on Windows & Linux.

The issue is not seen on Windows.

Tested the same on win10, mac 10.11.5 and Linux 14.04 chrome version 54.0.2837.0 - all the videos in youtube are playing fine on scrolling the page up and down and on reloading the page multiple times.

Adding TE-Verified labels